BIOL 1070 Final – Notes
Weeks 1-3 1. Mussels of the great lakes region (Evolution)
Weeks 4-7 2. Forest biodiversity (Evolution and Ecology)
Weeks 9-13 3. Arctic ecosystem (Evolution, Ecology, and Physiology)
Evolution: study of both adaptive and non-adaptive change over time in populations, the origin
and extinction of species, and the relationship among living things.
Ecology: study of interrelationships between organisms and both living (biotic) and non-living
(abiotic) components of their environments.
Physiology: study of organism structure and function, including homeostasis and encompassing
cells, tissues, organs, and body systems.
Impact of climate change on arctic ecosystem – Why be concerned?
Polar ice caps melting, sea level rising. Less ice = more absorbtion of UV rays + heat by the
ocean and land. Less available land when ice melts (sea level rises) = more densely populated.
1. Biological impacts (biodiversity changes, disease, migration)
2. Political and economic impacts (arctic sovereignty, natural resources, environmental
3. Aesthetics (landscapes, tourism)
4. Cultural changes (traditional hunting practices)
What are the consequences of an arctic ecosystem 8 degrees warmer?
1. key abiotic variables in arctic
2. examples of arctic plants and animals
3. how temperature changes impact organisms at different levels of organization
What we need to know
1. how climate change impacts organisms on different time scales
2. how climate change impacts plants and lichens
3. physiological responses to temperature change in animals
4. predicting long term trends in arctic populations
1 - How climate change impacts organisms on different time scales
Example Question: Arctic fox remain active when arctic temperatures fall to -50 degrees. Several
strategies for surviving this climate are listed below. Select the physiological strategy that is
correctly matched with a time scale and level of organization.
Answer: E) Arctic fox has small ears, a short muzzle, relatively short legs and a small rounded
body that limits heat loss in the cold (= generational, whole organism)
Time domains for temperature change
Arctic plants and animals have lived in the arctic ecosystem for thousands of years. They must
cope with temperature change on many different time scales: Acute, Chronic, and
What you need to know:
-is the organism unicellular or multicellular?
-is the animal an endotherm or ectotherm?
-is the animal able to avoid the temperature change? -are there behavioural responses that the animal can invoke to reduce the impact of the
-what types of physiological responses are possible and at what level (cell, tissue, organ, etc.)?
1. Acute response: Increase in ambient temperature, regulation or increase in body
2. Chronic response: Chronic stress, Physiological (acclimatization to new thermal regime),
population range changes
3. Generational response: Extirpation or extinction, natural selection (adaptation to new
Acclimatization: adjustment by individual to chronic stress, physiological processes change to
better function under new conditions, change is reversible and may be reversible
-ULT shifts because winter fish acclimatize to a lower range of temperatures relative to summer
Question: Do mush ox acclimatize to seasonal changes in climatic conditions?
Answer: Ox pelage goes through seasonal changes, migrate down to lowlands in winter,
highlands in summer.
Structure is linked to function -parallel arrangements of vessels
Reconstruction of hemoglobin of wooly mammoth:
Level of organization: Macromolecule
Hypothesis: Wooly mammoth hemoglobin had properties that allowed it to function in cold
extremities and appendages, despite having a warmer core temperature.
Prediction: Hemoglobin structure will be more similar to that of arctic animals than closely
related tropical elephants.
Results: WM hemoglobin unloaded oxygen more efficiently in colder conditions than hemoglobin
from living elephants.
Implications: Biochemical specialization may have been involved in the exploitation of high
latitude environments by this African derived elephantid species during Pleistocene period.
2 – How climate change impacts plants and lichens
Adaptations in arctic plants and lichens
What abiotic factors challenge arctic plants?
What are the adaptations of arctic plants?
At minimum, what do ALL plants need to survive and reproduce?
-Chloroplast: Thylakoid membrane, Starch grain
-Vacuole: Vacuole, Tonoplast
-Nucleus: Nuclear pore, Nuclear envelope, Nucleus 3 – Physiological responses to temperature change
Classifying animals in terms of responses to environment
In ectotherms, the Q10 provides a measure of how sensitive metabolic processes are to
temperature change. Q10 can be determined on any rate process (breathing rate, heart rate,
Conformer: allow the internal environment to follow changes in the external environment.
Regulator: regulators maintain a constant internal environment (homeostasis) in the face of a
varying external environment.
Can an animal be both a conformer and a regulator? Thermocontrollers, but regulate the
constant internal ion concentration. Heterothermy: Endothermic at certain times or in certain tissues but not at all times or in all
Ex. Different times: humming birds daily hibernation
Different tissues: Bumble bees thorax is hotter than other parts
Metabolic rate and temperature graph: Left = ectotherms, right = endotherms
-When it gets cold, oxygen consumption increases because the body needs more energy and
oxygen to stay warm. When you’re overheated, your body uses energy + oxygen to stay cold.
Cost: dependent on environment, can’t always perform to maximum levels
Benefit: don’t have to spend energy to maintain core temperature
Endothermy (Bergman’s rule)
Body size tends to be larger for species of endotherms living in the cold.
(Low surface area : volume – ratio = easier to retain heat.)
Arctic Fox: acclimatized to summer conditions begin
to increase oxygen consumption at a higher ambient
temperature than foxes acclimatized to winter
conditions. This may relate to differences in the
insulating properties of their fur in different seasons.
3 - Physiological responses to temperature change in
animals Animals can gain or lose heat in many different ways:
4 – Predicting long term trends in arctic
Supercooling and Ice Nucleation
-Pure water can be cooled to below 0 degrees without freezing
-Physical disruption or addition of an ice-nucleating agent causes rapid freexing of supercooled
Freezing-point depression: colligative antifreezes
Solution of water freezes at 0 degrees, colligative antifreezes lower freezing point of body fluids
by increasing concentration of solutes.
Freezing-point depression: noncolligative antifreezes
Noncolligative antifreezes lower the freezing point of body fluids because of specialized chemical
*Strategies for overwintering in ectotherms
What strategies do arctic ectotherms use to survive winter conditions? Strategies Freeze tolerance Freeze intolerance
1. behavioural avoidance
2. production of
3. synthesis of ice
(temperate NOT arctic
Thinking like a biologist
Observation: Antifreeze proteins increase in fall and decrease in spring in arctic marine fishes
Question: What is the trigger for synthesis of antifreeze proteins in arctic marine fish?
Hypothesis: In cold water marine fish, the trigger for synthesis of antifreeze protein is…….
Prediction: If so then……
What are the consequences of an Arctic ecosystem 8C warmer?
Physiology : the biological impact of rising temperatures depends on the physiological sensitivity
of organisms to temperature change.
Evolution and ecology: biological impact of rising temperatures also depends on differences in
survival and/or reproduction among individuals on the basis of differences in heritable
traits/characteristics as these individuals interact with each other and their environment
-tundra and tropical forest ecosystems will loose the greatest number of species because these
ecosystems have high richness and slight changes in temperature will disrupt fine-scaled climatic
-Arctic ecosystems will gain the greatest number of species because these ecosystems have low
richness and slight increases in temperature will create new niches allowing many species to
-Arctic ecosystems will have the highest rates of species turnover as entirely new communities
and ecosystems establish (forest, wetlands) with slight increases in temperature
What is richness? Count of species
Will there be bears?
What information do you consider to be the most important in determining if there will be bears in
the arctic following the current trend in climate change?
-competition Is there available habitat?
Can bears move long distances?
Can bears change their ecology?
-polar bears can probably den successfully in other than permafrost features, but will this affect